78209389 has 8 divisors (see below), whose sum is σ = 80241920. Its totient is φ = 76186656.

The previous prime is 78209387. The next prime is 78209413. The reversal of 78209389 is 98390287.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78209389 - 2¹ = 78209387 is a prime.

It is a super-2 number, since 2×78209389² = 12233417055506642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78209387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15364 + ... + 19810.

It is an arithmetic number, because the mean of its divisors is an integer number (10030240).

Almost surely, 2^78209389 is an apocalyptic number.

It is an amenable number.

78209389 is a deficient number, since it is larger than the sum of its proper divisors (2032531).

78209389 is a wasteful number, since it uses less digits than its factorization.

78209389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4899.

The product of its (nonzero) digits is 217728, while the sum is 46.

The square root of 78209389 is about 8843.6072391304. The cubic root of 78209389 is about 427.6478546516.

The spelling of 78209389 in words is "seventy-eight million, two hundred nine thousand, three hundred eighty-nine".